Modular Backplane for an Industrial Controller

ABSTRACT

An industrial controller with a modular backplane includes multiple modules, where each module includes a base and a chassis. Electrical connectors located on each side of the base engage the base of an adjacent module such that the bases are electrically connected. The backplane is defined by and extends through each of the bases connected to each other. A chassis is inserted into each base. Each chassis includes an embedded switch and a local circuit. The embedded switch is in communication with the base, and the local circuit performs the operation of the corresponding module. The embedded switch receives data transmitted along the backplane between bases. The embedded switch reads the data intended for the module and passes the data to the local circuit for further processing. Similarly, the embedded switch receives data from the local circuit and inserts the data on the backplane for transmission to the appropriate module.

This application is a continuation of and claims priority to U.S.application Ser. No. 16/366,604, filed Mar. 27, 2019, the entirecontents of which is incorporated herein by reference.

BACKGROUND INFORMATION

The subject matter disclosed herein relates to industrial controlsystems and, in particular, to a method and system for providing amodular backplane in an industrial controller for scalability andconfigurability.

Industrial controllers, such as programmable logic controllers (PLC's)or programmable activity controllers (PAC's), are specialized electroniccomputer systems used for the control of industrial machines orprocesses, for example, in a factory environment. Industrial controllersdiffer from conventional computers in a number of ways. Physically, theyare constructed to be substantially more robust against shock and damageand to better resist external contaminants. The industrial controllersperform real-time control and execute languages allowing readycustomization of programs to comport with a variety of differentcontroller applications. Industrial controllers may have a userinterface for accessing, controlling and/or monitoring the industrialcontroller, such as through a locally connected terminal having akeyboard, mouse and display.

As is known to those skilled in the art, industrial controllers areconfigurable according to the requirements of the controlled machine orprocess. The industrial controller includes a processor module andvarious input and output modules. The input modules receive signals fromsensors, switches, and other devices providing the operating status ofthe controlled machine or process. The processor module executes acontrol program which receives the input signals and generates outputsignals in response to the operating status of the controlled machine orprocess. The output signals are delivered from the output modules toactuators, indicators, and other devices to achieve a desired operationof the controlled machine or process. Still other modules, such as acounter module, network module, and the like may be included in thecontrolled machine or process.

In order to receive input signals from and provide output signals tovarious modules, the processor module must communicate with each module.Typically, a dedicated communication bus, also known as a backplane, isprovided between the processor module and each additional moduleconnected to the processor module. The backplane is configured toaccommodate high-speed and reliable communications between modules.Additionally, because the bus is a dedicated bus configured tocommunicate between known modules, communication can occur in apredefined format, such as a proprietary communication protocol orutilizing a predefined communication schedule that requires little or nodata overhead, such as headers, footers, checksums, and the like.However, each module must utilize the same protocol and be configured tocommunicate according to the predefined format on the backplane.

Typically, a backplane is configured in a linear, or daisy-chain,format. Modules are mounted in a rack or otherwise mounted adjacent toeach other and data is transmitted between adjacent modules. A linearconfiguration, however, is not without certain drawbacks. If one moduleis removed from the system, the chain is broken and modules cannotcommunicate with modules beyond the open slot.

Thus, it would be desirable to provide an industrial controller with alinear backplane that maintains communication between modules when onemodule fails or is removed.

In certain applications, such as a safety application or ahigh-reliability application, the industrial controller may beconfigured to use redundant devices and/or redundant communicationbusses to achieve a desired a safety rating or a desired operationalreliability for the application. In such an application, the industrialcontroller may include two processor modules, pairs of input modules,pairs of output modules, and dual communication paths between each ofthe modules. Adding the redundant configuration is not without certaindrawbacks. When an industrial controller is configured in the redundantconfiguration, every module is duplicated increasing hardware expense aswell as installation and commissioning expense. In addition, if a userwishes to upgrade an existing system, the existing hardware needs to beremoved and replaced.

In certain applications, however, it would be desirable to provide anindustrial controller which can provide a range of capability, includingsimple, general applications, high reliability applications, or acombination thereof. Thus, it would be desirable to provide a modularindustrial controller that permits flexible configuration andinterconnection between different types of modules and that alsosimplifies upgrades of existing systems.

BRIEF DESCRIPTION

The subject matter disclosed herein describes a modular industrialcontroller with a backplane that maintains communication between moduleswhen one module fails or is removed and that facilitates an upgradebetween redundant and non-redundant modules. Each module includes a baseand a chassis. Connectors, which may be either electrical or optical,connect each base to another base. A first connector may be located onone side of the base and a second connector may be located on theopposite side of the base, where the first connector is complementary tothe second connector. The first connector of one base engages the secondconnector of another base, such that bases mounted adjacent to eachother are electrically connected and communicatively coupled to eachother. The backplane is defined, in part, by each base and extendsthrough each of the bases connected to each other. Optionally, a cablemay be run between a first connector and a second connector joining, forexample, a first row of modules and a second row of modules andextending the backplane between rows of modules.

A chassis is inserted into each base. Each chassis includes an embeddedswitch and an additional local circuit. The embedded switch is incommunication with the base and the local circuit is configured toperform the operation of the corresponding module. The embedded switchreceives data transmitted along the backplane between bases and isconfigured to identify data intended for the module in which the switchis embedded. The embedded switch reads the data intended for the moduleand passes the data to the local circuit for further processing.Similarly, the local circuit may generate data for transmission to othermodules along the backplane. The embedded switch receives the data fromthe local circuit and inserts the data on the backplane for transmissionto the appropriate module.

According to one embodiment of the invention, a modular backplane for anindustrial controller includes a first module and multiple additionalmodules. The first module includes a first base and a first chassis. Thefirst base defines, in part, a backplane for the industrial controller,and the first chassis is removably mounted to the first base. The firstchassis includes a first embedded switch in communication with the firstbase. Each additional module includes a second base and a secondchassis. The second base defines, in part, the backplane for theindustrial controller and is in communication with at least one of thefirst base and the second base of another additional module. The secondchassis is removably mounted to the second base and includes a secondembedded switch in communication with the second base. The firstembedded switch is operative to receive first data from a first networkat a first port and receive second data from a backplane at second andthird ports. The first network is arranged in a single-path star format,and the backplane extends between the first module and each of theplurality of additional modules. The first embedded switch is alsooperative to transmit the first and second data via one of the first,second, and third ports.

According to another embodiment of the invention, a modular backplanefor an industrial controller includes a first module and multipleadditional modules. The first module includes a first base and a firstchassis. The first base defines, in part, a backplane for the industrialcontroller. The first base includes first and second connectors andfirst and second ports. The first port is in communication with thefirst connector, and the second port is in communication with the secondconnector. The first chassis is mounted to the first base and includes afirst embedded switch. The first embedded switch has a first port incommunication with the first port of the first base to communicate onthe backplane via the first connector and a second port in communicationwith the second port of the first base to communicate on the backplanevia the second connector. The first embedded switch is configured toreceive a plurality of first data packets from a network operativelyconnected to the first embedded switch and to receive a plurality ofsecond data packets from the backplane. The first embedded switch isfurther configured to transmit the first and second data packets toeither the network or the backplane. Each additional module includes asecond base and a second chassis, where the second base defines, inpart, the backplane for the industrial controller. The second baseincludes a first connector, a second connector, a first port, a secondport, a first switch, and a second switch. The first connector of thesecond base is operative to be connected to the second connector oneither the first base of the network module or the second base ofanother additional module. The first port is in communication with thefirst connector of the second base, and the second port is incommunication with the second connector of the second base. The firstswitch is operative to selectively connect the first port between thefirst connector and either the second chassis mounted to the second baseor the second switch of the second base. The second switch is operativeto selective connected the second port between the second connector andeither the second chassis or the first switch of the second base. Thesecond chassis is mounted to the second base and includes a secondembedded switch. The second chassis has a first port and a second port,the first port of the second chassis is in communication with the firstport of the second base, and the second port of the second chassis is incommunication with the second port of the second base. The secondembedded switch is operative to receive the data from the backplane viaone of the first and second ports in the second embedded switch.

According to still another embodiment of the invention, an industrialcontroller with a modular backplane includes a processor module, anetwork module, and multiple additional modules. The processor moduleincludes a first base and a first chassis. The first base defines, inpart, a backplane for the industrial controller, and includes a firstelectrical connector. The first chassis is removably mounted to thefirst base and includes a first embedded switch in communication withthe first electrical connector. The network module includes a secondbase and a second chassis. The second base defines, in part, thebackplane for the industrial controller, includes a second electricalconnector on a first side of the second base, and includes a thirdelectrical connector on a second side of the second base. The secondchassis includes a second embedded switch in communication with thesecond and third electrical connectors. Each of the additional modulesincludes a third base and a third chassis. The third base defines, inpart, the backplane for the industrial controller. The third baseincludes a fourth electrical connector on a first side of the third baseand a fifth electrical connector on a second side of the third base. Thethird chassis includes a third embedded switch in communication with thefourth and fifth electrical connectors. The first electrical connectoris removably connected to either the second electrical connector or thefourth electrical connector for one of the additional modules, the thirdelectrical connector is removably connected to the fourth electricalconnector for one of the additional modules, and the fifth electricalconnector is removably connected to either the second electricalconnector or the fourth electrical connector for one of the additionalmodules. The first, second, and third bases define the backplane for theindustrial controller, and the first, second, and third embeddedswitches receive data from the backplane for the corresponding chassisin which the switch is embedded. Either the first or second embeddedswitch receives data from a network connected to either the processormodule or the network module, respectively.

These and other advantages and features of the invention will becomeapparent to those skilled in the art from the detailed description andthe accompanying drawings. It should be understood, however, that thedetailed description and accompanying drawings, while indicatingpreferred embodiments of the present invention, are given by way ofillustration and not of limitation. Many changes and modifications maybe made within the scope of the present invention without departing fromthe spirit thereof, and the invention includes all such modifications.

BRIEF DESCRIPTION OF THE DRAWINGS

Various exemplary embodiments of the subject matter disclosed herein areillustrated in the accompanying drawings in which like referencenumerals represent like parts throughout, and in which:

FIG. 1 is a schematic representation of an industrial control system inaccordance with one embodiment of the present invention;

FIG. 2 is an isometric view of a bank of remote modules for theindustrial control system of FIG. 1;

FIG. 3 is an isometric view of a single base for an I/O module of FIG.1;

FIG. 4 is a schematic representation of an industrial control system inaccordance with another embodiment of the present invention;

FIG. 5 is a partial block diagram representation of the industrialcontrol system of FIG. 1;

FIG. 6 is a block diagram representation of an industrial controllerincorporating one embodiment of the present invention;

FIG. 7 is a block diagram representation of an industrial controllerincorporating another embodiment of the present invention;

FIG. 8 is a block diagram representation of an industrial controllerincorporating another embodiment of the present invention;

FIG. 9 is a block diagram representation of the industrial controller ofFIG. 6 with a module missing;

FIG. 10 is a block diagram representation of an industrial controllerincorporating another embodiment of the present invention;

FIG. 11 is a block diagram representation of an industrial controllerincorporating another embodiment of the present invention; and

FIG. 12 is a block diagram representation of an industrial controllerincorporating another embodiment of the present invention.

In describing the various embodiments of the invention which areillustrated in the drawings, specific terminology will be resorted tofor the sake of clarity. However, it is not intended that the inventionbe limited to the specific terms so selected and it is understood thateach specific term includes all technical equivalents which operate in asimilar manner to accomplish a similar purpose. For example, the word“connected,” “attached,” or terms similar thereto are often used. Theyare not limited to direct connection but include connection throughother elements where such connection is recognized as being equivalentby those skilled in the art.

DETAILED DESCRIPTION

The various features and advantageous details of the subject matterdisclosed herein are explained more fully with reference to thenon-limiting embodiments described in detail in the followingdescription.

Turning initially to FIG. 1, an exemplary industrial control systemincorporating one embodiment of a modular backplane in an industrialcontroller 10 is illustrated. The industrial controller 10 is configuredto control operation of a machine or process 15. The industrialcontroller may be made up of numerous different modules connectedtogether in a rack or mounted to a rail. Additional modules may be addedor existing modules removed and the industrial controller 10reconfigured to accommodate the new configuration. Optionally, theindustrial controller 10 may have a predetermined and fixedconfiguration. According to the illustrated embodiment, each module 12,14, 16, 18, 20 includes a base 22, 24, 26, 28, 30 mounted to a DIN rail11 and a chassis 32, 34, 36, 38, 40 which is plugged in to therespective

base. The illustrated industrial controller 10 includes a power supplymodule 12, a processor module 14, a network module 16, an input module18, and an output module 20. The input and output modules 18, 20 may beselected according to the application requirements and may be, forexample, analog or digital input or output modules, which will bereferred to herein generally as an I/O module. Input signals 19 provideinformation to the industrial controller 10 regarding operation of thecontrolled machine or process 15 and are provided to the input module18. The input modules 18 communicate the input signals 19 to theprocessor module 14 via a backplane as will be discussed in more detailbelow. The processor module 14 executes a control program to generateoutput signals 21 responsive to the input signals 19. The output signalsare transmitted from the processor module 14 to the output module 20 viathe backplane. The output signals 21 are, in turn, transmitted from theoutput module 20 to controlled devices to achieve desired operation ofthe controlled machine or process 15. Additionally, while only a singleinput and a single output module are illustrated, it is contemplatedthat various numbers of input and/or output modules may be usedaccording to the requirements of the controlled machine or process 15and may be connected locally by mounting additional bases to the DINrail and plugging the bases together.

Optionally, a remote I/O rack 50 may provide additional input and outputmodules 54, 56, 58 and is connected to the network module 16 via anetwork cable 17 and an I/O adapter module 52. Each remote rack 50 maybe positioned at varying positions about the controlled machine orprocess 15. Each remote rack 50 may be modular and made up of numerousdifferent modules connected together in a rack or mounted to a rail.Additional modules may be added or existing modules removed and theremote rack 50 reconfigured to accommodate the new configuration.Optionally, the remote rack 50 may have a predetermined and fixedconfiguration. As illustrated, the remote rack 50 includes an adaptermodule 52, configured to communicate on an industrial network 17 such asEthernet/IP, DeviceNet, or ControlNet to the network module 16, andadditional input and output modules 54, 56, 58. Each input module isconfigured to receive input signals from the controlled machine orprocess 15, and each output module is configured to provide outputsignals to the controlled machine or process 15. Optionally, still othermodules may be included in the remote rack 50. According to oneembodiment, the remote rack 50 may include an additional processormodule 14, where each processor module 14 is configured to control aportion of the controlled machine or process.

It is understood that the industrial control network, industrialcontroller 10, and remote racks 50 may take numerous other forms andconfigurations without deviating from the scope of the invention. Withreference, for example, to FIG. 4, the industrial controller 10 mayinclude a rack 9 in which each module is inserted. The rack 9 may serveas a base for each module. The power supply 12 may be removably mountedor may be a fixed component and integrally mounted to the rack 9. Theprocessor module 14, network module 16, input module 18, and outputmodule 20 are removably inserted into the rack 9. The rack 9 may beconfigured as a base with 4 slots and each module configured as achassis which is inserted into one slot of the base as will be discussedin more detail below. Optionally, the rack 9 may include other numbersof slots without deviating from the scope of the invention.

Turning next to FIG. 2, the remote bank of modules 50 in accordance withone embodiment of the present invention is illustrated. The bank ofmodules 50 includes a series of enclosures arranged from left to right,side-by-side, with complex shapes that may be generally described ascubic. The series of enclosures include a left most adapter module 52,followed by a first I/O module 54, a second I/O module 56, and a thirdI/O module 58. Each module is held in close proximity to the other,thereby facilitating connections, either electrical or optical, side byside to establish communications. Each module may be held by attachmentto a DIN rail 51, see also FIG. 3. In an alternative embodiment, one ormore modules may be held with greater separation and having electricalconnections supported by network cabling.

The adapter module 52 may further comprise a plurality of variousconnectors 53, as well as visual displays 55 and/or LED's for systemmonitoring, located on one or more respective surfaces. Possibleconnectors may include, for example, a plurality of RJ-45 networkconnectors for network connectivity of the bank, for example, to aremote computer or to a Programmable Logic Controller (PLC); a UniversalSerial Bus (USB) and/or IEEE 1394 connector for a locally connectedterminal or device; a network connector corresponding to a particularindustrial network; or any other advantageous connector as known in theart. The adapter module 52 also includes a power connector 57 forpowering the bank.

It is contemplated that each module may include a base 72, 74, 76, 78and a chassis 62, 64, 66, 68 mounted to the base. Different I/O modules54, 56 may utilize a common base where each base 74, 76 includes commoncomponents between modules 54, 56, such as interconnections betweenadjacent modules, terminals 65, and connectors 71 (see also FIG. 3) tothe chassis 64, 66. Each chassis 64, 66 may include components thatdiffer between modules, such as logic circuits to receive inputs, driveoutputs, or process analog or digital signals. Each chassis 64, 66 maybe plugged into the base 74, 76 and the chassis and base providedtogether as a complete I/O module 54, 56. The other modules, such as theadapter module 52 and the third I/O module 58 may similarly include abase 72, 78 and chassis 62, 68 configuration where the base 72, 78 forthe adapter module 52 and the third I/O module 58 are different fromeach other and also different than the base 74, 76 for the first andsecond I/O module 54, 56. According to another embodiment of theinvention, each module may have a single housing or, optionally, acombination of modules including a single housing or a base and chassisconstruction may be utilized. According to still another embodiment ofthe invention a single base may be configured to receive two, four, orstill other numbers of chassis. The base for each module includeselectrical connectivity and base logic to facilitate a backplane betweenthe modules.

I/O modules 54, 56 and 58 may further comprise a plurality of electricalterminals (or terminal blocks) 65 and 69 respectively, for receivingconductors exposed on the surface of each enclosure to releasably retainelectrical conductors communicating between the I/O module and a deviceon the controlled processes or machines (not shown). Each chassis of theI/O module may resemble the other in size, color and shape, though theseaspects may differ by function. The number of terminals 65, 69 presentin each terminal block may differ according to the base and to thefunction of the I/O module. The I/O modules 54, 56, and 58 may beconfigured, for example, to receive either an analog or digital input oroutput. The input or output voltages may be, for example, a DC voltagebetween 5-48 VDC or an AC voltage of 120 VAC.

Referring now to FIG. 3, an exemplary base 74,76 for an I/O module inaccordance with an embodiment of the present invention is illustrated.The I/O module base 74, 76 is a common base used between the first I/Omodule 54 and the second I/O module 56 in the illustrated embodiment.The base has a housing with a left side 81 and a right side 82. Eachside may further comprise a releasable connector 84 with complementaryconnectors supported on each side and exposed to connect to adjacentmodules on the left and right sides, such that adjacent connectors canengage each other and establish communication between adjacent bases. Itis contemplated that the connector 84 may be an electrical connector,optical connector, or any suitable connector to establish communicationbetween adjacent bases. For discussion herein, the illustratedembodiment includes an electrical connector 84 and an electricalconnection is established between adjacent bases. The I/O module base74, 76 may further comprise a releasable mechanical connector 86 forholding the I/O module in position relative to the adjacent modules byattachment, for example, to a DIN rail 51. As described above, each I/Omodule base 74, 76 may further comprise a plurality of electricalterminals (or terminal blocks) 65 for receiving conductors exposed onthe surface of the enclosure to releasably retain electrical conductorscommunicating between devices on the controlled processes or machinesand I/O function card held within the chassis of the I/O module. One ormore slots 71A, 71B may be provided on the base to establish electricalconnections between the base 74, 76 and the chassis 64, 66 mounted onthe base. One or more mating receptacles 89 may also be provided toestablish a mechanical connection with and positively retain the chassisto the base. Although discussed above with respect to the remote bank ofmodules 50, the modular structure of bases 72, 74, 76, 78 and chassis62, 64, 66, 68 described with respect to the remote bank 50 is similarlyutilized by modules 12, 14, 16, 18, 20 on the main rack of theindustrial controller 10, where each module 12, 14, 16, 18, 20 includesabase 22, 24, 26, 28, 30 and a chassis 32, 34, 36, 38, 40, respectively.

Referring next to FIG. 5, a portion of the exemplary industrial controlsystem of FIG. 1 is illustrated in block diagram form. Due to factorssuch as the increasingly distributed nature of the control network andthe increasing capability and reduced cost of processing devices, it iscontemplated that each of the modules in the system may include aprocessor 90-94 and a memory device 95-99. The processors 90-94 areconfigured to execute instructions and to access or store operating dataand/or configuration parameters stored in the corresponding memorydevice 95-99. The processors 90-94 may be any suitable processoraccording to the module requirements. It is contemplated that processors90-94 may include a single processing device or multiple processingdevices executing in parallel and may be implemented in separateelectronic devices or incorporated on a single electronic device, suchas a field programmable gate array (FPGA) or application specificintegrated circuit (ASIC). Similarly, the memory devices 95-99 may be asingle device, multiple devices or may be incorporated in part or inwhole within the FPGA or ASIC. Each of the modules also includes a clockcircuit 100-104, and each clock circuit 100-104 may be synchronized withthe other clock circuits 100-104 according to, for example, theIEEE-1588 clock synchronization standard. Each clock circuit 100-104generates a time signal configurable to report the present time accurateto either microseconds or nanoseconds. Communication between modulesmounted in the same rack or contained within a single housing occurs viaa backplane 200 and a corresponding backplane connector 201. Modulescommunicating via network media 17 include ports 105-107 configured toprocess the corresponding network protocol. Each input module 54includes input terminals 110 configured to receive the input signals 19from the controlled machine or process 15. The input module 54 alsoincludes any associated logic circuitry 114 and internal connections112, 116 required to process and transfer the input signals 19 from theinput terminals 110 to the processor 93. Similarly, each output module56 includes output terminals 120 configured to transmit the outputsignals 21 to devices in the controlled machine or process 15. Theoutput module 56 also includes any associated logic circuitry 124 andinternal connections 122, 126 required to process and transfer theoutput signals 21 from the processor 94 to the output terminals 120.

In operation, the industrial controller 10 provides a modular backplane200 between the various modules defining the industrial controller.Turning next to FIG. 6, an exemplary embodiment of an industrialcontroller 10A is illustrated. The illustrated embodiment includes aprocessor module 14, a network module 16, two input modules 18, and anoutput module 20. It is contemplated that the industrial controller 10communicates with other devices, such as another industrial controller,an operator interface, a programming terminal, and the like via anetwork 13, 17. The network may include standard network devices andprotocols, such as Ethernet, TCP/IP, and the like, industrial networkdevices and protocols, such as Ethernet/IP, DeviceNet, ControlNet, orthe like, or a combination thereof.

A device connected via the network communicates in a point-to-pointconfiguration, generating data packets for and transmitting those datapackets to other devices with which the first device wishes tocommunicate. The data packets transmitted via the point-to-pointconfiguration are referenced herein as being in a first protocol,requiring, for example, a source address, a destination address,connection information, and the like. According to the illustratedembodiment, the network 13 is connected to the network module 16. Incertain embodiments, the network module 16 may include multiple networks13, 17 such as those illustrated in FIG. 1. It is further contemplatedthat the network 13 may be connected to the processor module 14, asshown in FIG. 11. It is contemplated that in alternate embodiments aportion of, or the entire functionality of, the network module 16 may beincorporated within the processor module 14 without deviating from thescope of the invention.

Data communicated in a point-to-point configuration between devicesremotely connected via the first protocol may be more efficientlycommunicated between modules connected to each other using a backplane200 via a second protocol. The second protocol may utilize, for example,a proprietary data structure, where data for each module 14, 16, 18, 20in the industrial controller 10A is inserted in a predefined order,format, or combination thereof and transmitted with minimal or no headerinformation. Each module 14, 16, 18, 20 in the industrial controller 10Ais configured to insert and/or extract data according to the proprietarydata structure, maximizing the bandwidth of data to be transmitted viathe backplane 200. Various other protocols for communication via thebackplane may be utilized without deviating from the scope of theinvention.

According to one embodiment of the invention, the data received from thenetwork 13 in the first protocol is converted to the second protocolprior to transmission on the backplane 200. The embedded switch 25within the network module 16 may be configured to convert the data fromone protocol to another protocol prior to transmitting the data.Optionally, a local logic circuit may be provided within the networkmodule 16, where the local logic circuit is configured to convert thedata between protocols. In alternate embodiments, the network module 16may be a dedicated conversion module where the network data packets arereceived from the network 13, for example, by the processor module 14and transmitted via a first portion of the backplane 200 from theprocessor module base to the network module base 26 and to the embeddedswitch 25 in the conversion module 16. The embedded switch 25 may thenconvert the data from the first protocol to the second protocol.According to still another embodiment of the invention, the processormodule 14 may be configured to receive the data from the network 13 inthe first protocol and convert the data to the second protocol fortransmission via the backplane 200.

According to another embodiment of the invention, the data received fromthe network 13 in the first protocol may be passed directly along thebackplane 200 in the first protocol. The embedded switch 25 within thenetwork module 16 may be configured to receive the data packet from thenetwork 13, identify a module along the backplane 200 for which thepacket is intended, and retransmit the data packet along the backplane200 to the intended recipient.

According to yet another embodiment of the invention, the data receivedat the network module may be from another backplane 200 and formatted inthe second protocol. The network module 16 may be connected via anetwork 17 to a remote rack or to another industrial controllerconfigured to control another portion of the controlled machine orprocess. Rather than converting data between protocols for transmission,a first network module 16 on the remote rack or in the remote industrialcontroller may transmit data directly via the second protocol to asecond network module 16. The embedded switch 25 in the second networkmodule 16 identifies the data packet as being formatted in the secondprotocol and passes the data packet directly along the backplane 200where one or more modules may interact with the data packet according tothe configuration of and/or the data present within the received datapacket.

With reference again to FIG. 6, the processor module 14 includes a base24 and a chassis 34 removably mounted to the base 24. The base 24includes a port 180 in communication with a complementary port 184 inthe chassis 34. The ports 180,184 are connected by terminals in theelectrical connector 71 on the mating surface of the base 24 andcomplementary terminals in an electrical connector on the mating surfaceof the chassis 34. The chassis 34 of the processor module 14 alsoincludes a local control circuit 33 which performs the functions of themodule and includes, for example, the processor 90, memory 95, and clockcircuit 100 for the processor module 14.

An embedded switch 23 within the chassis 34 of the processor module 14receives data packets from the base 24 and/or data packets from anetwork 13 (e.g., when the network 13 is connected to the processormodule 14) and routes the packets to the appropriate destination. If thenetwork 13 is connected to the processor module 14, data packets in thefirst protocol are being received at the processor module. In someembodiments, a network module 16 may transmit data packets received fromthe network 13 to the processor module 14 in the first protocol. Otherdata packets may be received at the embedded switch 23 from thebackplane 200 in the second protocol. The embedded switch 23 isoperative to determine whether a data packet is in the first or secondprotocol, extract data from the data packet, convert data received ineither the first or second protocol to the other protocol if necessary,and transmit the data to the appropriate destination.

For example, the embedded switch 23 in the processor module 14 mayreceive a first data packet from the network 13 where the first datapacket includes data for the local control circuit 33 within theprocessor module 14. The embedded switch 23 is operative to extract thedata and transmit the data to the local control circuit 33. The embeddedswitch 23 may also receive a second data packet from the network 13where the second data packet includes data to be output as controlsignals on the output module 20. The embedded switch 23 converts thedata from the first protocol to the second protocol and transmits thedata via the backplane 200 to the output module 20. Still other datapackets may be received from the backplane 200, for example, from theinput modules 18 which include data corresponding to the operatingstatus of the controlled machine or process 15. The embedded switch 23may pass the data through to the local control circuit 33 for use in acontrol program executing on the processor module 14. Still other datafrom the input modules 18 may need to be transmitted to a remotestation, such as an operator interface or a data logging terminal. Theembedded switch 23 may convert the data from the second protocol to thefirst protocol and transmit the data via the network 13 to theappropriate location.

The network module 16 also includes a base 26 and a chassis 36 removablymounted to the base 26. The base 26 includes a first port 160 and asecond port 162 in communication with complementary ports 164 and 166,respectively, in the chassis 36. The ports 160-166 are defined byterminals in the electrical connector(s) 71 on the mating surface of thebase 26 and complementary terminals in an electrical connector on themating surface of the chassis 36. An embedded switch 25 within thechassis 36 of the network module 16 receives data packets from the base26 and/or data packets from a network 13 if the network 13 is connectedto the network module 16. Although not illustrated in FIG. 6, thenetwork module 16 may also include a local control circuit whichincludes, for example, the processor 91, memory 96, and clock circuit101 for the network module 16.

Additional modules, such as the input modules 18 and the output module20, also include a base 28, 30 and a chassis 38, 40 removably mounted tothe respective base. The bases 28, 30 each include a first port 170 anda second port 172 in communication with a complementary port 174 and176, respectively, in the chassis 38, 40. The ports 170-176 are definedby terminals in the electrical connector(s) 71 on the mating surface ofthe base 28, 30 and complementary terminals in an electrical connectoron the mating surface of the chassis 38, 40. Embedded switches 27, 29within the chassis 38, 40 of the input modules 18 and the output module20 receive data packets from the respective base 28, 30. Each input andoutput module 18, 20 includes a local control circuit 37, 39 whichincludes, for example, the processor, memory, clock circuit, inputcircuits, and output circuits for the respective modules.

Each base 24-30 in the illustrated embodiment of FIG. 6 may be mountedto a DIN rail 51 and electrically connected to one (if positioned on anend) or both (if positioned between the end modules) of the basesadjacent to the module via electrical connectors 84 on the base. Thebases 24-30 of each module define a backplane 200 between modules in theindustrial controller 10A. With reference also to FIG. 9, each base mayalso include one or more switches 150 which allows a chassis on themodules to be inserted or removed and still maintain communicationbetween modules. For ease of illustration, each switch 150 is shown as asingle pole double throw switch which is electrically connected to oneof the electrical connectors 84 on the base and alternately connected tothe chassis, if mounted, or to the other electrical connector, if thechassis is not mounted.

With reference to an input module 18, shown in FIG. 9, each switch 150A,150B is in a first position when the chassis 38 is not mounted to thebase 28B. A first switch 150A, in communication with a first electricalconnector 84 on a first side of the base 28B, establishes a normallyclosed connection to a first throw of the first switch 150A. The firstthrow of the of the first switch 150A is electrically connected to afirst throw of a second switch 150B within the base 28B. The secondswitch 150B, in communication with a second electrical connector 84 on asecond side of the base 28B, similarly establishes a normally closedconnection to the first throw of the second switch 150B. As a result,when no chassis 38 is connected to the base 28B, an electricalconnection on the backplane 200 is established through the base 28Bbetween the first and second electrical connectors 84 via the first andsecond switches 150A, 150B and via an internal connection between thefirst and second switches 150A, 150B.

When the chassis 38 of the input module 18 is mounted to the base 28,the chassis 38 causes the state of the switch 150 to change. In oneembodiment, a mechanical coupling occurs, for example, via one of themating receptacles 89 in the base 28 and a complementary memberextending from the mating surface of the chassis 38 into the matingreceptacle. The mechanical coupling causes the connection in each switch150A, 150B between the first pole and the first throw to open andestablishes a second electrical connection between the first pole and asecond throw. The second throw for each switch 150A, 150B is connectedto one of the ports 170, 172 communicating with the chassis 38. Thus,when the chassis 38 is mechanically mounted to the base 28A, thebackplane 200 is routed through the embedded switch 27 within thechassis 38. The electrical connection along the backplane is establishedfrom the first electrical connector 84 through the first switch 150A tothe first port 170 of the base 28, through the complementary port 174 ofthe chassis, and to the embedded switch 27 within the chassis 38. Theelectrical connection continues from the embedded switch 27 within thechassis 38, through the second port 176 of the chassis 38, to thecomplementary second port 172 in the base 28A, through the second switch150B, and to the second electrical connector 84. The insertion/removalof the chassis 38 to the base 28 activates the switch 150 providing forcontinuous connection of the backplane through the base 28 regardless ofwhether the chassis 38 is mounted to the base 28.

According to another embodiment, the switch 150 may be a solid-stateswitch defined, for example, by one or more transistors. Connection ofthe chassis 38 to the base 28 creates an electrical path that causes theswitch to change state. Thus, just as with a mechanical switch, when thechassis 38 is mounted to the base 28, each switch 150 routes thebackplane 200 through the embedded switch 27 within the chassis 38. Whenthe chassis 38 is not mounted to the base 28, the switch 150 routes thebackplane 200 through the base 28, providing a continuous communicationpath between adjacent bases 28 regardless of whether the chassis 38 ismounted to the base 28.

Thus, if a chassis 38 for a module fails, needs to be replaced, or isbeing upgraded, the processor module 14, and the control programexecuting within the processor module, may be configured to continueoperation of at least a portion of the controlled machine or process 15with the remaining modules for the industrial controller 10A, providingthe devices connected to the chassis 38 being replaced are not requiredfor continued operation of that portion of the controlled machine orprocess 15.

With reference to FIG. 12, it is contemplated that each base may beconfigured without a switch 150 and may provide a single path throughthe embedded switch for the respective module connected to the base. Insuch a configuration, it is further contemplated that an endcap 31 maybe provided to provide the ability to replace a chassis 38 for at leasta single module at a time while the processor module continues operationof at least a portion of the controller machine or process 15. The endcap 31 establishes a ring configuration on the backplane 200 providingfor communication in either direction around the backplane 200. When asingle chassis 38 is removed from its base 28, each remaining chassis isstill able to communicate to the other chassis in one direction oranother. Thus, the chassis 38 for at least one module may be replaced orupgraded at a time if the control program is configured to continueoperation of the remaining portions of the controlled machine or process15.

According to the embodiment of the industrial controller 10A shown inFIGS. 6 and 9, the processor module 14 and/or the network module 16 mayreceive data in a first protocol from the network 13 in a single-pathstar configuration and the modules may communicate to each other alongthe backplane 200 in a second protocol via a one-half ringconfiguration. The data transmitted in the single-path starconfiguration is point-to-point data transmitted via the network. Thenetwork is a single-path star configuration because a single network 13is provided and a single communication path exists between theindustrial controller 10A and other devices remotely connected via thenetwork 13. The single-path star configuration is in contrast to theredundant star configuration which will be discussed in more detailbelow. The data transmitted between modules is transmitted in a one-halfring configuration, or in a linear topology, between modules becausethere is a single communication pathway between modules. Thetransmission pathway is bidirectional/full-duplex, allowing data to betransmitted from the output module 20 to the processor module 14 or fromthe processor module 14 to the output module 20. Similarly, data may betransmitted to or from any intermediate module (e.g., the network module16 and the input module 18) and one of the end modules (e.g., theprocessor module 14 and the output module 20) in either direction.However, any particular data transfer between modules has a singlebidirectional/full-duplex communication path along the backplane 200between the modules.

As also illustrated in FIGS. 6 and 9, each base 28, 30 of the additionalmodules may further include an optional communication path 151 extendingbetween the first and second electrical connectors on each side of thebase. The optional communication path 151 may be utilized to convert theone-half ring communication in the additional modules to a full ringcommunication among the additional modules.

With reference now to FIG. 7, a second embodiment of the industrialcontroller 10B is illustrated. The second embodiment of the industrialcontroller 10B is configured to receive data in a first protocol from anetwork 13 in a redundant star configuration and the modules areconfigured to communicate between each other along the backplane 200 ina second protocol utilizing a full ring configuration. An end cap 31connected to a second electrical connection of the base 30 for theoutput module 20 establishes an electrical connection from the linearcommunication path of the one-half ring configuration, discussed above,to the optional communication path 151 within each of the additionalmodules. This end cap defines a first end of the full ring, where thesecond end is defined within the base 26′ of the network module 16′, aswill be discussed in more detail below.

The redundant star configuration of the industrial controller 10Butilizes a second embodiment of the base 24′, 26′ for the processormodule 14′ and network module 16′ respectively. Each redundant base 24′,26′ includes connections for two chassis to be mounted to the base. Theredundant processor module base 24′ includes a first processor modulechassis 34A and a second processor module chassis 34B, where eachprocessor module chassis 34A, 34B may be identical in configuration tothe processor module chassis 34 discussed above. Although the redundantprocessor module 14′ is illustrated with two ports between the embeddedswitch 23A, 23B in each chassis 34A, 34B and the redundant base 24′, theprocessor module chassis 34 discussed above with respect to FIG. 6, maysimilarly include two ports, where one of the ports is unused in thesingle-path configuration. The redundant network module base 26′includes a first network module chassis 36A and a second network modulechassis 36B, where each network module chassis 36A, 36B may be identicalin configuration to the network module chassis 36 discussed above.Although the redundant network module 16′ is illustrated with four portsbetween the embedded switch 25A, 25B in each chassis 36A, 36B and theredundant base 26′, the network module chassis 36 discussed above withrespect to FIG. 6, may similarly include four ports, where two of theports are unused in the single-path configuration.

The processor module 14′ and/or the network module 16′ receives data ina first protocol from a redundant network in the redundant-starconfiguration. The redundant processor module 14′ includes a base 24′configured to receive two chassis 34A, 34B, each removably mounted tothe base 24′. The base 24′ includes four ports 180, 180′, 181 and 181′(referred to herein as 180-181′), where two ports are in communicationwith complementary ports in each chassis 34A, 34B. The first port 180 inthe base 24′ is connected to a first port 184B in the second chassis34B, the second port 181 in the base 24′ is connected to a second port185B in the second chassis 34B, the third port 180′ in the base 24′ isconnected to a first port 184A in the first chassis 34A, the fourth port181′ in the base 24′ is connected to a second port 185A in the firstchassis 34A. The ports 180-181′ are defined by terminals in theelectrical connector(s) 71 on the mating surface of the base 24′ andcomplementary terminals in an electrical connector on the matingsurfaces of each chassis 34A, 34B. Each chassis 34A, 34B of theprocessor module 14′ also includes a local control circuit 33A, 33Bwhich performs the functions of the module and includes, for example,the processor, memory, and clock circuit for the corresponding chassisof the processor module 14′.

The redundant network module 16′ also includes a base 26′ configured toreceive two chassis 36A, 36B, each removably mounted to the base 26′.The base 26′ includes eight ports 160-163′, where four ports are incommunication with complementary ports in each chassis 36A, 36B. Thefirst port 160 in the base 26′ is connected to a first port 164B in thesecond chassis 36B, the second port 161 in the base 26′ is connected toa second port 165B in the second chassis 36B, the third port 162 in thebase 26′ is connected to a third port 166B in the second chassis 36B,the fourth port 163 in the base 26′ is connected to a fourth port 167Bin the second chassis 36B, the fifth port 160′ in the base 26′ isconnected to a first port 164A in the first chassis 36A, the sixth port161′ in the base 26′ is connected to a second port 165A in the firstchassis 36A, the seventh port 162′ in the base 26′ is connected to athird port 166A in the first chassis 36A, and the eighth port 163′ inthe base 26′ is connected to a fourth port 167A in the first chassis36A. The ports 160-163′ are defined by terminals in the electricalconnector(s) 71 on the mating surface of the base 26′ and complementaryterminals in an electrical connector on the mating surfaces of eachchassis 36A, 36B.

For convenience, the redundant network will be described with connectionto the network module 16′ receiving the data from the network as shown,but it is understood that a redundant network may similarly be connectedto the processor module 14′ in a manner similar to the single-pathnetwork discussed above. The redundant network includes a first network13A connected to the first chassis 36A and a second network 13Bconnected to the second chassis 36B. Identical data may be transmittedin tandem in redundant data packets on each network 13A, 13B from aremote device to the redundant network module 16′. The first embeddedswitch 25A in the first chassis 36A for the redundant network module 16′receives the data packets from the first network 13A, and the secondembedded switch 25B in the second chassis 36B for the redundant networkmodule 16′ receives the data packets from the second network 13B. Theredundant network module 16′ is further configured to compare theredundant data received from each network 13A, 13B to each other toverify correct transmission of data. It is contemplated that oneembedded switch 25A may be configured to perform the comparison andreceive the data from the other embedded switch 25B via the base 26′.Optionally, a local logic circuit in one of the two chassis 36A, 36B maybe configured to perform the comparison. According to still anotherembodiment of the invention, full redundancy may provide for bothembedded switches and/or both local logic circuits comparing the datareceived at one chassis with the data received at the other chassis.When the redundant network module 16′ verifies that the data has beenproperly received from the redundant networks 13A, 13B in the firstprotocol. Each chassis converts the data to the second protocol fortransmission to the appropriate module via the redundant backplane 200′.

As previously indicated, the network module base 26′ for the redundantnetwork includes a second end of the device level ring for thebackplane. In addition to the end cap 31 connected to the opposite endof the ring, a full ring topology is established between the networkmodule 16′ and each of the additional modules 18, 20. Data may betransmitted around the ring in either direction to each of the modules.As a result, even in the event of a single failure of the hardware alongthe ring, each module will still have a communication path to the othermodules. Each embedded switch 25A, 25B may transmit data received alongthe ring topology to one of the additional modules 18, 20. The embeddednetwork switch 27, 29 in the respective additional module receives theredundant data packets in the second protocol and verifies correctreception of data within the additional module. Similarly, data fromeach additional module may be transmitted back to each of the embeddedswitches 25A, 25B. Each embedded switch 25A, 25B may pass the data tothe processor module 14′ which determines which data is required for usewithin the processor module 14′ and which data should be transmittedexternally via the networks 13A, 13B. The processor module 14′ maygenerate a data packet for transmission via the networks 13A, 13B andpass the data packet back to the network module 16′ to send out via thenetworks 13A, 13B. Optionally, the embedded switches 25A, 25B or anadditional local logic circuit (not shown) within the network module 16′may be configured to identify at least a portion of data from theadditional modules that is to be transmitted via the networks 13A, 13Band converts the data to a separate data message in the first protocolfor retransmission via the redundant networks 13A, 13B.

Previously, FIGS. 6 and 9 have been discussed with respect to asingle-path star network and one-half ring configuration. Each of theseconfigurations provides for a single channel of communication whether inthe point-to-point first protocol or in the linear backplane secondprotocol. FIG. 7 illustrates a redundant star network and a full ringconfiguration. Each of these configurations provides for redundantchannels of communication whether in the first protocol forpoint-to-point communication or in the second protocol for backplanecommunication. However, the proposed modular system also allows forinterconnection of modules with different numbers of communicationchannels.

Turning next to FIG. 8, a third embodiment of the industrial controller10C is illustrated. The third embodiment of the industrial controller10C is configured to receive data in a first protocol from a network 13Aor 13B in the redundant star configuration while the modules areconfigured to communicate between each other along the backplane 200 inthe one-half ring configuration. The end cap 31 shown in FIG. 7 isremoved. The rest of the components discussed above with respect to FIG.7 are utilized. A redundant processor module 14′ and a redundant networkmodule 16′ are combined with a pair of input modules 18 and an outputmodule 20. Although the optional communication path 151 is connected atthe left side of each module to the adjacent module and is furtherconnected at the first input module 18 to one end of a device level ringwithin the base 26′ of the redundant network module 16′, because the endcap 31 is removed, the ring is incomplete and no communications occuralong the optional communication path 151.

With comparison also to FIG. 6, it is observed that the additionalmodules (e.g., the input modules 18 and the output module 20) in FIG. 8are identical to those disclosed in FIG. 6. Thus, the same additionalmodules could be utilized in a single-path and one-half ring system asthose used in a partially redundant system. Similarly, the processormodule 14′ and the network module 16′ illustrated in the partiallyredundant system are identical to those illustrated in the fullyredundant system. The modularity of the modules allows for a reducednumber of modules to be manufactured for different systemconfigurations. Further, should an upgrade from a single-path andone-half ring system, as shown in FIG. 6, to the partially redundantsystem of FIG. 8 be desired, only a portion of the modules need to bechanged, reducing the overall cost of upgrading the industrialcontroller 10.

Turning next to FIG. 10, still another embodiment of the industrialcontroller 10D is illustrated. The industrial controller 10D of FIG. 10includes an additional data appliance module 41 connected to the system.The additional data appliance 41 includes a base 44 and a chassis 42removably mounted to the base 44. Similar to the base 24 for theprocessor module 14, disclosed in FIG. 6, the base 44 for the additionaldata appliance includes a port 180 in communication with a complementaryport 184 in the chassis 42. The ports 180, 184 are connected byterminals in the electrical connector 71 on the mating surface of thebase 44 and complementary terminals in an electrical connector on themating surface of the chassis 42. Additionally, the base 24 includes asecondary communication path 186 between the first electrical connectorand the second electrical connector on opposite sides of the base 44.The secondary communication path 186 carries data communications on thebackplane 200 from the network module 16 to the additional dataappliance 41. It is contemplated that the additional data appliance 41may be configured for point-to-point communications and be configured tocommunicate via a suitable point-to-point communication protocol withthe network module 16. An identical base 44 may be utilized by theprocessor module 14 since it contains an identical connection betweenthe network module 16 and the embedded switch 23 within the processormodule 14. Optionally, a single base 44 for the processor module 14 maybe utilized in either application, where the base 44 includes thesecondary communication path 186 but it is not utilized when anadditional data appliance module 41 is not connected to the processormodule 14.

The chassis 42 of the additional data appliance module 41 includes anembedded switch 43 and a local control circuit 45 which performs thefunctions of the module. The local control circuit 45 may include, forexample, a processor, memory, and a clock circuit for the data appliancemodule 41. The data appliance may be configured to execute acomputationally intensive process, such as motion profile generation,harmonic analysis, and the like, which may be desirable to offload fromthe processor module 14. Alternately, the data appliance may be athird-party module with specific functionality not otherwise availableor alternately available to functionality provided by the processormodule 14.

With reference next to FIG. 11, yet another embodiment of the industrialcontroller 10E is illustrated. The embodiment illustrated in FIG. 11 isagain a single-path star and one-half ring system similar to thatdiscussed above with respect to FIG. 6. However, it is contemplated thata base 28′ may be provided for the additional modules that provides formultiple chassis to be plugged into the base 28′. According to theillustrated embodiment, two input module chassis 38 are plugged into asingle input module base 28′. The two-slot base 28′ includes separatepairs of switches (e.g., 150A, 150B and 150C, 150D) for each chassis 38allowing the base to be utilized with no chassis 38, a single chassis38, or with two chassis 38 plugged in to the base.

It should be understood that the invention is not limited in itsapplication to the details of construction and arrangements of thecomponents set forth herein. The invention is capable of otherembodiments and of being practiced or carried out in various ways.Variations and modifications of the foregoing are within the scope ofthe present invention. It also being understood that the inventiondisclosed and defined herein extends to all alternative combinations oftwo or more of the individual features mentioned or evident from thetext and/or drawings. All of these different combinations constitutevarious alternative aspects of the present invention. The embodimentsdescribed herein explain the best modes known for practicing theinvention and will enable others skilled in the art to utilize theinvention.

I claim:
 1. An industrial controller with a modular backplane, wherein the industrial controller is configured to control operation of a machine or process, the industrial controller comprising: a processor module configured to execute a control program which controls operation of the machine or process, the processor module including: a first base including a connector, and a first chassis removably mounted to the first base, the first chassis including a first embedded switch; and a plurality of additional modules, each of the plurality of additional modules including: a second base, the second base including at least one connector configured to be connected to either the connector of the first base or to the at least one connector of another additional module, and a second chassis removably mounted to the second base, the second chassis including a second embedded switch, wherein: a backplane defines a communication path between the first base and the second base of each of the plurality of additional modules, and the first embedded switch is operative to: receive first data from an external network operatively connected to the first chassis, transmit the first data to the backplane via the first base, receive second data from the first base, wherein the second data is communicated via the backplane, and transmit the second data to the external network.
 2. The industrial controller of claim 1, wherein the first embedded switch is operative to: receive the first data in a first communication protocol and the second data in a second communication protocol, convert the first data to the second communication protocol and convert the second data to the first communication protocol, and transmit the first data in the second communication protocol via the backplane and transmit the second data in the first communication protocol via the external network.
 3. The industrial controller of claim 1, wherein: the at least one connector on the second base of each of the plurality of additional modules includes a first connector and a second connector, a first communication path and a second communication path are defined through the second base of each of the plurality of additional modules between the first connector and the second connector; and the backplane is defined within the second base of each of the plurality of additional modules by at least one of the first communication path and the second communication path.
 4. The industrial controller of claim 3 further comprising an end cap removably connected to the second connector of the second base of one of the plurality of additional modules, wherein the end cap joins the first communication path and the second communication path through the end cap, defining one end of a ring network for the backplane.
 5. The industrial controller of claim 1, wherein: the processor module further includes a third chassis removably mounted to the first base; the third chassis includes a third embedded switch in communication with the first base; the external network is operatively connected to both the first chassis and the third chassis; and the first embedded switch and the third embedded switch are configured to operate in tandem to: receive the first data from the external network, transmit the first data to the backplane via the first base, receive the second data from the first base, and transmit the second data to the external network.
 6. The industrial controller of claim 1, wherein at least one of the plurality of additional modules includes a third chassis removably mounted to the second base, and wherein the third chassis includes a third embedded switch in communication with the corresponding second base.
 7. The industrial controller of claim 1, wherein: the at least one connector on the second base of each of the plurality of additional modules includes a first connector and a second connector, at least one communication path is defined through the second base of each of the plurality of additional modules between the first connector and the second connector, the second base of each of the plurality of additional modules further includes at least one switch, the at least one switch establishes a first communication path for the backplane between the first connector and the second connector of the second base when the second chassis is removed from the second base, and the at least one switch establishes a second communication path for the backplane between the first connector and the second embedded switch and a third communication path for the backplane between the second connector and the second embedded switch when the second chassis is mounted to the second base.
 8. An industrial controller with a modular backplane, wherein the industrial controller is configured to control operation of a machine or process, the industrial controller comprising: a processor module configured to execute a control program which controls operation of the machine or process; a network module operatively connected to the processor module, the network module including: a first base including a connector, and a first chassis removably mounted to the first base, the first chassis including a first embedded switch; and a plurality of additional modules, each of the plurality of additional modules including: a second base, the second base including at least one connector configured to be connected to either the connector of the first base or to the at least one connector of another additional module, and a second chassis removably mounted to the second base, the second chassis including a second embedded switch, wherein: a backplane defines a communication path between the first base and the second base of each of the plurality of additional modules, and the first embedded switch is operative to: receive first data from an external network operatively connected to the first chassis, transmit the first data to the backplane via the first base, receive second data communicated via the backplane from the first base, and transmit the second data to the external network.
 9. The industrial controller of claim 8, wherein the first embedded switch is operative to: receive the first data in a first communication protocol and the second data in a second communication protocol, convert the first data to the second communication protocol and convert the second data to the first communication protocol, and transmit the first data in the second communication protocol via the backplane and transmit the second data in the first communication protocol via the external network.
 10. The industrial controller of claim 8, wherein: the at least one connector on the second base of each of the plurality of additional modules includes a first connector and a second connector; a first communication path and a second communication path are defined through the second base of each of the plurality of additional modules between the first connector and the second connector and the backplane is defined within the second base of each of the plurality of additional modules by at least one of the first communication path and the second communication path.
 11. The industrial controller of claim 10 further comprising an end cap removably connected to the second connector of the second base of one of the plurality of additional modules, wherein the end cap joins the first communication path and the second communication path through the end cap, defining one end of a ring network for the backplane.
 12. The industrial controller of claim 8, wherein: the network module further includes a third chassis removably mounted to the first base; the third chassis includes a third embedded switch in communication with the first base; the external network is operatively connected to both the first chassis and the third chassis; and the first embedded switch and the third embedded switch are configured to operate in tandem to: receive the first data from the external network, transmit the first data to the backplane via the first base, receive the second data from the first base, and transmit the second data to the external network.
 13. The industrial controller of claim 8, wherein at least one of the plurality of additional modules includes a third chassis removably mounted to the second base, and wherein the third chassis includes a third embedded switch in communication with the corresponding second base.
 14. The industrial controller of claim 8, wherein: the at least one connector on the second base of each of the plurality of additional modules includes a first connector and a second connector, at least one communication path is defined through the second base of each of the plurality of additional modules between the first connector and the second connector, the second base of each of the plurality of additional modules further includes at least one switch, the at least one switch establishes a first communication path for the backplane between the first connector and the second connector of the second base when the second chassis is removed from the second base, and the at least one switch establishes a second communication path for the backplane between the first connector and the second embedded switch and a third communication path for the backplane between the second connector and the second embedded switch when the second chassis is mounted to the second base.
 15. An industrial control system configured to control operation of a machine or process, the industrial control system comprising: an industrial network; and an industrial controller, including: a processor module configured to execute a control program which controls operation of the machine or process, the processor module including: a first base including a connector, and a first chassis removably mounted to the first base, the first chassis including a first embedded switch; and a plurality of additional modules, each of the plurality of additional modules including: a second base, the second base including at least one connector configured to be connected to either the connector of the first base or to the at least one connector of another additional module, and a second chassis removably mounted to the second base, the second chassis including a second embedded switch, wherein: a backplane defines a communication path between the first base and the second base of each of the plurality of additional modules, and either the first or second embedded switch is operative to: receive first data from the industrial network; transmit the first data to the backplane, receive second data communicated from the backplane, and transmit the second data to the industrial network.
 16. The industrial control system of claim 15 wherein the first embedded switch is connected to the industrial network and wherein the first embedded switch is operative to: receive the first data in a first communication protocol and the second data in a second communication protocol, convert the first data to the second communication protocol and convert the second data to the first communication protocol, and transmit the first data in the second communication protocol to the backplane and transmit the second data in the first communication protocol to the industrial network.
 17. The industrial control system of claim 15 wherein: one of the plurality of additional modules is a network module, the second embedded switch in the network module is connected to the industrial network, and the second embedded switch in the network module is operative to: receive the first data in a first communication protocol and the second data in a second communication protocol, convert the first data to the second communication protocol and convert the second data to the first communication protocol, and transmit the first data in the second communication protocol to the backplane and transmit the second data in the first communication protocol to the industrial network.
 18. The industrial control system of claim 15, wherein: the at least one connector on the second base of each of the plurality of additional modules includes a first connector and a second connector, a first communication path and a second communication path are defined through the second base of each of the plurality of additional modules between the first connector and the second connector, and the backplane is defined within the second base of each of the plurality of additional modules by at least one of the first communication path and the second communication path.
 19. The industrial control system of claim 18 further comprising an end cap removably connected to the second connector of the second base of one of the plurality of additional modules, wherein the end cap joins the first communication path and the second communication path through the end cap, defining one end of a ring network for the backplane.
 20. The industrial control system of claim 15, wherein: the at least one connector on the second base of each of the plurality of additional modules includes a first connector and a second connector, at least one communication path is defined through the second base of each of the plurality of additional modules between the first connector and the second connector, the second base of each of the plurality of additional modules further includes at least one switch, the at least one switch establishes a first communication path for the backplane between the first connector and the second connector of the second base when the second chassis is removed from the second base, and the at least one switch establishes a second communication path for the backplane between the first connector and the second embedded switch and a third communication path for the backplane between the second connector and the second embedded switch when the second chassis is mounted to the second base. 